The present invention relates to a light control circuit for an illuminated vanity mirror assembly and particularly to a dimming circuit and a method of manufacturing the same.
Illuminated vanity mirror assemblies are frequently installed in visors for vehicles. U.S. Pat. No. 4,000,404 discloses such a system including, in FIG. 15 thereof, a dimming control for providing variable adjustment of the light intensity from the lamps associated with the vanity mirror. The system disclosed is relatively expensive requiring several solid state circuit elements in addition to a variable resistor for providing the dimming control. The utilization of a conventional rheostat, although providing desired dimming, adds considerable bulk and/or expense to a dimming control and can provide a relatively concentrated source of heat which could result in damage to the typically polymeric core utilized in the manufacture of the vanity. Other dimming controls for a vanity mirror installed in a visor are disclosed in U.S. Pat. No. 4,586,788 showing a dimming switch to assure that when the covered vanity mirror is opened, it is always opened in the dim position and U.S. Pat. No. 4,227,242 showing a dimming control as a function of cover movement. The latter two patents provide dimming control primarily to assure that when the cover is opened on the covered vanity mirror assembly, the user is not temporarily blinded by the high intensity of the light.
U.S. Pat. No. 4,879,637 provides a vanity mirror having a frame and an insulated circuit board with a conductor and screen printed resistor thereon. Wiper contacts selectively engage the resistor and conductor to provide a variable resistance coupled with lamp means for providing an adjustable current supplied to the lamps from the vehicle's power supply to control the light intensity. U.S. Pat. No. 4,744,645 discloses a vanity mirror with a circuit also printed on a insulative substrate which is a polymeric film and which includes an adhesive layer for attaching the film to the mirror back. The circuit includes a resistor and a wiper arm for dimming lamps associated with a vanity mirror package for use with a visor.